1. Field of the Invention
The present invention relates to a guide roller which rolls along a rail provided on a vehicle body side and is rotatably and pivotally supported by a support member connected to a slide door.
2. Description of the Prior Art
In a slide door for a vehicle, the slide door is slidably supported along a vehicle body side wall by rollably engaging an upper guide roller provided in a front end upper portion of the slide door, a center guide roller provided in a central portion in a height direction of a rear end, and a lower guide roller provided in a front end lower portion with an upper rail provided in an upper edge portion of a vehicle body opening, a center rail provided in a central portion in the height direction of a side wall in a vehicle body rear portion adjacent to the vehicle opening, and a lower rail provided in a lower edge portion of the vehicle opening, respectively, so that the slide door can be opened and closed.
As a guide roller of a slide door, there has been used a bearing type roller in which an outer peripheral surface and a top surface of an outer ring are covered with a synthetic resin as shown in JP-A-2003-176661 (see FIGS. 3 and 8), for example. The reason why the bearing type guide roller is used like this is that when a roller constructed as a resin solid roller with the small number of components is used, there arises the disadvantage that the resin solid roller is asymmetrically worn due to a load of the slide door and prevented from smoothly rotating, and thereby the resin solid roller breaks and falls off from a vehicle body in the worst case. The bearing type guide roller has the advantage that the roller itself is difficult to break and hardly falls off from the vehicle body even if the resin part breaks because at least a structure body of the roller is an outer ring made of metal (bearing steel).